Follicle number
Developing follicles are identified separately in the right and left ovaries.
Fertility ultrasound · Ovulation & cycle monitoring
Follicular Tracking Ultrasound Scan
Serial pelvic ultrasound monitoring of ovarian follicle growth, the dominant follicle and endometrial development to support natural conception, ovulation induction, IUI or IVF cycle monitoring.
- £219 per scan
- No GP referral
- Internal scan only with consent
- London & St Albans
Per tracking scan£219Written report includedMost cycles need 2–4 scans
Follicle measurementsBoth ovaries assessed
Endometrial assessmentThickness and pattern
Serial monitoringGrowth compared between visits
Clinic-ready reportShare with fertility team
About the scan
What is follicular tracking?
Follicular tracking is a series of cycle-timed pelvic ultrasound scans that follow the development of ovarian follicles over several days. The scan measures the number and size of developing follicles, identifies the leading follicle and assesses the endometrium.
Repeat measurements show how the ovaries and lining are changing during a natural or treatment cycle.
Important: follicular tracking helps estimate ovulation timing but cannot guarantee that a follicle contains a mature egg and cannot by itself confirm fertility.
What is measured
Measurements at each tracking scan
Measurements are documented consistently so change can be compared between visits.
Follicle diameter
Relevant follicles are measured in millimetres and compared with previous scans.
Dominant follicle
The leading follicle is identified and followed between visits where appropriate.
Endometrial thickness
The womb lining is measured in millimetres in relation to the cycle stage.
Endometrial pattern
The lining appearance is documented, including trilaminar or later-cycle appearance where relevant.
Post-ovulation features
Follicle collapse, corpus luteum and free fluid may support that ovulation has occurred.
Why patients book
Natural and assisted-conception monitoring
The scan can follow your own cycle or a fertility clinic’s monitoring protocol.
Natural conception
Helps estimate the fertile window by monitoring follicle development directly.
Ovulation induction
Monitors ovarian response while medication decisions remain with the prescribing clinician.
IUI monitoring
Provides follicle and lining measurements for treatment planning.
IVF monitoring
Provides serial ovarian measurements according to the fertility clinic’s protocol.
Cycle timing
When should tracking start?
Timing depends on cycle length, treatment and whether baseline or post-ovulation assessment is needed.
Baseline when requested
Often used before a medicated cycle or when a fertility clinic asks for baseline measurements.
Common starting window
A frequent first tracking window in a natural cycle, adjusted to your usual cycle length.
Repeat monitoring
Return timing is guided by current follicle size, growth and treatment protocol.
Confirmation scan
Post-ovulation appearances may support that ovulation has occurred.
Cycle Day 1: use the first day of full menstrual bleeding rather than light spotting.
How the scan is performed
Transvaginal imaging for detail — only with consent
Transvaginal ultrasound usually gives the clearest view of small follicles and the endometrium, but it is not compulsory.
- Cycle day and fertility medication are reviewed.
- Both ovaries are assessed systematically.
- Relevant follicles are measured.
- Endometrial thickness and pattern are recorded.
- Previous measurements are compared on repeat visits.
Your choice: a transvaginal examination is performed only with explicit consent and can be declined or stopped. A transabdominal alternative is available, although detail may be reduced.
Clinical limitations
What follicular tracking cannot tell you
Ultrasound is one part of fertility assessment.
Egg quality
Ultrasound measures the follicle but cannot determine the biological or genetic quality of the egg.
Tubal patency
Standard ultrasound cannot prove the fallopian tubes are open. HSG or HyCoSy may be needed.
Sperm
Sperm count, movement and morphology require semen analysis.
Exact ovulation time
The scan estimates the fertile window but cannot guarantee the exact time of ovulation.
Hormone levels
AMH, FSH, LH, oestradiol and progesterone require blood testing.
Pregnancy outcome
Correctly timed ovulation does not guarantee conception or implantation.
Before your appointment
How to prepare
Cycle timing and your fertility protocol matter more than complex physical preparation.
Know your cycle day
Bring the date of the first day of your last full menstrual bleed.
Bring your protocol
If a fertility clinic is managing your cycle, bring its requested scan instructions.
List medication
Tell us about letrozole, clomifene, gonadotrophins or trigger medication.
Bladder
Empty for transvaginal imaging; comfortably full if scanning abdominally.
At each visit
What happens during the appointment?
- 1
Cycle information
Cycle day, usual length, medication and clinic protocol are confirmed.
- 2
Consent and method
The scan method is explained and consent confirmed.
- 3
Measurements
Follicles and endometrial thickness/pattern are documented.
- 4
Results explained
Measurements are discussed and compared with previous visits where relevant.
- 5
Next scan timing
Repeat timing is guided by current findings and the fertility protocol. Medication decisions stay with the prescribing clinician.
Book online
Book your Follicular Tracking Ultrasound Scan
Use the dedicated PrivateSono booking page to choose clinic, date and appointment time.
Most cycles require more than one scan. Book each appointment according to your cycle timing or fertility-clinic protocol.
Clinic locations
Central London and St Albans
Central London
27 Welbeck Street
London W1G 8EN.
Book Central London →St Albans
54–56 Victoria Street
St Albans AL1 3HZ.
Book St Albans →What is a follicular tracking scan?+
It is a series of pelvic ultrasound scans that measure ovarian follicles and the endometrial lining during a menstrual or treatment cycle.
How much does each scan cost?+
The current PrivateSono price is £219 per follicular-tracking scan.
How many scans will I need?+
There is no fixed number. Many cycles need around 2–4 scans, depending on cycle length, follicle growth and the treatment protocol.
When should the first scan be done?+
A common starting point is around Cycle Day 8–10 in a natural cycle. Baseline monitoring may be requested on Days 2–5, and treatment protocols may specify different timing.
How often are repeat scans needed?+
Repeat scans are commonly performed every 1–3 days once tracking is underway, but timing is individualised.
Is the scan transvaginal?+
Transvaginal ultrasound usually provides the most detailed follicle measurements. It is performed only with explicit consent. A transabdominal alternative is available.
Do I need a full bladder?+
For a transvaginal scan the bladder is emptied. For a transabdominal scan, a comfortably full bladder may be required.
Can the scan confirm ovulation?+
A post-ovulation scan may show follicle collapse, corpus luteum formation and free pelvic fluid, which can support that ovulation has occurred.
Can it tell me the exact day I will ovulate?+
The scan can estimate the likely fertile window from follicle development, but it cannot guarantee the exact timing of ovulation.
Can follicular tracking measure egg quality?+
No. Ultrasound can measure the follicle but cannot determine the genetic or biological quality of the egg.
Can it show whether my fallopian tubes are open?+
No. Standard pelvic ultrasound does not prove tubal patency. HSG or HyCoSy may be needed when this is clinically important.
Can I use this scan during IVF or IUI?+
Yes. Bring the monitoring protocol supplied by your fertility clinic. Medication and trigger decisions remain with the treating fertility clinician.
Do I need a GP referral?+
No. PrivateSono accepts direct self-referral for follicular tracking.
Will I receive a written report?+
Yes. Measurements and findings are documented in a clinical report that can be shared with your GP or fertility clinic when requested.
What if a cyst or other abnormality is seen?+
The finding is documented and further pelvic imaging, GP review or fertility-specialist review may be recommended depending on the appearance and clinical relevance.
Private fertility cycle monitoring
Book Follicular Tracking — £219
Ovarian follicle measurements, dominant follicle tracking and endometrial assessment.